The genome sequence of Trypanosoma cruzi, etiologic agent of Chagas disease     

El-Sayed NM  Myler PJ  Bartholomeu DC  Nilsson D  Aggarwal G  Tran AN  Ghedin E  Worthey EA  Delcher AL  Blandin G  Westenberger SJ  Caler E  Cerqueira GC  Branche C  Haas B  Anupama A  Arner E  Aslund L  Attipoe P  Bontempi E  Bringaud F  Burton P  Cadag E  Campbell DA  Carrington M  Crabtree J  Darban H  da Silveira JF  de Jong P  Edwards K  Englund PT  Fazelina G  Feldblyum T  Ferella M  Frasch AC  Gull K  Horn D  Hou L  Huang Y  Kindlund E  Klingbeil M  Kluge S  Koo H  Lacerda D  Levin MJ  Lorenzi H  Louie T  Machado CR  McCulloch R 《Science (New York, N.Y.)》2005,309(5733):409-415

Whole-genome sequencing of the protozoan pathogen Trypanosoma cruzi revealed that the diploid genome contains a predicted 22,570 proteins encoded by genes, of which 12,570 represent allelic pairs. Over 50% of the genome consists of repeated sequences, such as retrotransposons and genes for large families of surface molecules, which include trans-sialidases, mucins, gp63s, and a large novel family (>1300 copies) of mucin-associated surface protein (MASP) genes. Analyses of the T. cruzi, T. brucei, and Leishmania major (Tritryp) genomes imply differences from other eukaryotes in DNA repair and initiation of replication and reflect their unusual mitochondrial DNA. Although the Tritryp lack several classes of signaling molecules, their kinomes contain a large and diverse set of protein kinases and phosphatases; their size and diversity imply previously unknown interactions and regulatory processes, which may be targets for intervention.  相似文献   

Vertebrate-type intron-rich genes in the marine annelid Platynereis dumerilii     

Raible F  Tessmar-Raible K  Osoegawa K  Wincker P  Jubin C  Balavoine G  Ferrier D  Benes V  de Jong P  Weissenbach J  Bork P  Arendt D 《Science (New York, N.Y.)》2005,310(5752):1325-1326

Previous genome comparisons have suggested that one important trend in vertebrate evolution has been a sharp rise in intron abundance. By using genomic data and expressed sequence tags from the marine annelid Platynereis dumerilii, we provide direct evidence that about two-thirds of human introns predate the bilaterian radiation but were lost from insect and nematode genomes to a large extent. A comparison of coding exon sequences confirms the ancestral nature of Platynereis and human genes. Thus, the urbilaterian ancestor had complex, intron-rich genes that have been retained in Platynereis and human.  相似文献   

Survival of pathogens of Brussels sprouts (Brassica oleracea Gemmifera Group) in crop residues     

J. Köhl  M. Vlaswinkel  B. H. Groenenboom‐de Haas  P. Kastelein  R. A. van Hoof  J. M. van der Wolf  M. Krijger 《Plant pathology》2011,60(4):661-670

Mycosphaerella brassicicola (ringspot), Alternaria brassicicola and A. brassicae (dark leaf spot) and Xanthomonas campestris pv. campestris (black spot) can infect leaves of Brussels sprouts resulting in yield losses. Infections of outer leaves of sprouts cause severe losses in quality. Crop residues can be a major primary inoculum source of the pathogens. Their population dynamics were followed in residues of leaves and stalks of crops of Brussels sprouts during 24 months using real‐time PCR assays. Leaf residues on the soil surface or buried in soil decomposed within 4 months. However, residues of stalks were present in the field after 24 months. In such residues, M. brassicicola populations increased during the first 2 months, but decreased thereafter and the pathogen was found only occasionally in the second year. Alternaria brassicicola multiplied on stalks exposed on the surface of field soil and was present on such residues after 24 months. Survival was less on residues buried in soil. Alternaria brassicae population increased in stalks exposed on the soil surface during the first months but decreased thereafter under the detection limit. Xanthomonas campestris cv. campestris populations fluctuated in time but 1 × 10⁴ cells mg^?1 stalk residue were still found after 24 months. Additionally, the four pathogens were present in residues of 11 commercial rapeseed crops that were analysed. The observed variation in population sizes of the pathogens between individual pieces of crop residues indicates a stochastic spread of pathogens. Unravelling the underlying processes will support the development of novel methods for sustainable disease prevention.  相似文献   

Simulation of Nile tilapia (Oreochromis niloticus niloticus L.) culture in ponds, through individual-based modelling, using a population dynamic approach     

Gertjan J de Graaf  Pieter J Dekker  Bram Huisman  & Johan A J Verreth 《Aquaculture Research》2005,36(5):455-471

A simulation model for the production of the Nile tilapia (Oreochromis niloticus niloticus L.) for mixed‐ or mono‐sex culture and for poly‐culture with the African catfish (Clarias gariepinus Burchell 1822) or African snakehead (Parachanna obscura Günther 1861) is presented. The model is based on an exponential decay model used in population dynamics and follows an individual‐based approach. The model consists of a tilapia sub‐model representing population dynamics, growth and recruitment and a predator sub‐model representing the predation process and population dynamics and growth of the used predator. The model was calibrated with data on mixed‐ or mono‐sex culture of Nile tilapia and for poly‐culture with the African catfish or African snakehead obtained in Congo Brazzaville and validated with similar data from the Philippines, Thailand and the Ivory Coast. The model visualized major underlying processes in tilapia farming and aspects for further improvement of the model; growth is one of the most sensitive input parameters and should be quantitatively related to feeding level and feed quality; length at first maturity and quantification of the recruitment of Nile tilapia has a relatively large influence and recruitment should be related to the length of the females; prey–predator relations are too coarse and should be more fine‐tuned with the relation between prey size and predator size. Incorporation of these features would provide the basis of a model that can serve as a predictive and decision‐making support tool.  相似文献   

Factors influencing Ralstonia pseudosolanacearum infection incidence and disease development in rose plants     

Jan van der Wolf  Pieter Kastelein  Leo Poleij  Marjon Krijger  Odette Mendes  Nasim Sedighian  Caitilyn Allen  Peter Bonants  Viola Kurm 《Plant pathology》2022,71(7):1619-1632

Glasshouse experiments were conducted to study infection and disease development in rockwool-grown rose plants inoculated with Ralstonia pseudosolanacearum. A R. pseudosolanacearum strain isolated from rose plants was more aggressive than strains from anthurium or curcuma. The three rose cultivars tested, Avalanche, Red Naomi, and Armando, differed in susceptibility. At 20°C, the rose strain caused hardly any symptoms over a 6-week period, whereas at 28°C typical wilt symptoms were observed within 2 weeks after stem inoculation of Armando, the most susceptible cultivar. Inoculating roots with the rose strain resulted only in weak atypical symptoms. Nevertheless, inoculating roots of cv. Armando at a relatively low inoculum dose of 10⁴ cfu/ml led to high densities in the base of stems in one out of two experiments. R. pseudosolanacearum occasionally spread from stem inoculated plants with symptoms in rockwool slabs. This limited spread resulted in a low infection incidence, and only of plants directly adjacent to the plants with symptoms.  相似文献   

Reuse of dredged material as a way to tackle societal challenges   总被引：1，自引：1，他引：0  

Jos Brils  Pieter de Boer  Jan Mulder  Elmert de Boer 《Journal of Soils and Sediments》2014,14(9):1638-1641

Sediment is a natural resource that provides the foundation for living, working and building in lowland delta areas. A sustainable society, therefore, reuses dredged material as a valuable resource. Such reuse matches perfectly to the philosophy of a circular economy. However, it is not yet a common practice. Why is this, what are the bottlenecks and how do we overcome them? Here, we use the Netherlands as an example to illustrate possible solutions to these questions, although we believe that our messages and recommendations can be applied generically.  相似文献   

Nitric oxide metabolites in naturally occurring canine babesiosis.     

Linda S Jacobson  Remo G Lobetti  Pieter Becker  Fred Reyers  Tarquin Vaughan-Scott 《Veterinary parasitology》2002,104(1):27-41

Babesiosis, caused by the virulent haemoprotozoan parasite Babesia canis rossi, is an important disease of dogs in South Africa. The nitric oxide metabolites, nitrate and nitrite (collectively termed reactive nitrogen intermediates or RNIs) were measured in admission sera from dogs in a babesiosis-endemic area. Five groups were prospectively studied: mild uncomplicated (n=9), severe uncomplicated (severe anaemia) (n=10) and complicated babesiosis (n=11); and two groups of healthy aparasitaemic dogs: endemic controls from the study area (n=10) and experimental dogs kept in tick-free conditions (n=10). Four measures of RNI production were studied: (i) serum RNI; (ii) serum RNI/creatinine ratio; (iii) fractional clearance of RNI (FC(RNI)); (iv) fractional excretion of RNI (FE(RNI)). Marked elevations of serum RNI occurred in only two dogs, both in the severe uncomplicated group. The highest concentration (log value 5.29 micromol/l) was in a dog that died, but concentrations in the other four dogs that died were unremarkable (0, 0.34, 1.66 and 2.64 micromol/l). Age, appetite and free serum haemoglobin were significant covariates for measures of RNI production. There were no significant differences among the babesiosis groups for serum RNI. Adjustment for creatinine had minor effects on the results. All babesiosis groups had significantly higher serum RNI and RNI/creatinine than the tick-free control group, but did not differ from the endemic controls except for the severe uncomplicated group, which had higher RNI/creatinine. The complicated group had significantly lower FC(RNI) and FE(RNI) than all other groups, except for the tick-free control group, which had similar FE(RNI). The results indicate that, in an endemic area, measures of RNI production are unlikely to be useful indicators of severity or outcome in canine babesiosis.  相似文献   

Canal maintenance: a key to restructuring irrigation management     

Piet Sijbrandij  Pieter Van Der Zaag 《Irrigation and Drainage Systems》1993,7(3):189-204

Farmers becoming involved in canal mainentance is a recent trend in many government-managed irrigation systems. Before being able to assess the pitfalls and perspectives of this trend, it is necessary to examine in detail the issue of canal maintenance itself, an issue which has received relatively little attention. The paper focuses on canal maintenance in an irrigation system in Western Mexico, and finds that canal maintenance differs in several aspects from water distribution. A first difference is that water distribution often results in competition among water users along the same canal, whereas the need for canal maintenance may bring these people together in cooperation, which may help to forestall possible conflicts over water supply. A second important difference is that water distribution is directly productive, whereas canal maintenance involves the reproduction of the canal system, the (often considerable) costs involved being investments. In the case study reviewed, canal maintenance gave rise to certain relationships between different groups of people, and between them and the canal infrastructure, relationships which may not have been uncovered if only water distribution had been studied. It is argued that interventions aimed at handing over management responsibilities to water users would be more effective if such locally specific expressions of cooperation and initiative of the actors involved are taken as a starting point.  相似文献   

Competitive adsorption between beta-casein or beta-lactoglobulin and model milk membrane lipids at oil-water interfaces     

Waninge R  Walstra P  Bastiaans J  Nieuwenhuijse H  Nylander T  Paulsson M  Bergenståhl B 《Journal of agricultural and food chemistry》2005,53(3):716-724

This study investigated the competitive adsorption between milk proteins and model milk membrane lipids at the oil-water interface and its dependence on the state of the lipid dispersion and the formation of emulsions. Both protein and membrane lipid surface load were determined using a serum depletion technique. The membrane lipid mixture used was a model milk membrane lipid system, containing dioleoylphosphatidylcholine, dioleoylphosphatidylethanolamine, milk sphingomyelin, dioleoylphosphatidylserine, and soybean phosphatidylinositol. The model composition mimics the lipid composition of natural milk fat globule membranes. The interactions were studied for two proteins, beta-lactoglobulin and beta-casein. The mixing order was varied to allow for differentiation between equilibrium structures and nonequilibrium structures. The results showed more than monolayer adsorption for most combinations. Proteins dominated at the oil-water interface in the protein-emulsified emulsion even after 48 h of exposure to a vesicular dispersion of membrane lipids. The membrane lipids dominated the oil-water interface in the case of the membrane lipid emulsified emulsion even after equilibration with a protein solution. Protein displacement with time was observed only for emulsions in which both membrane lipids and beta-casein were included during the emulsification. This study shows that kinetics controls the structures rather than the thermodynamic equilibrium, possibly resulting in structures more complex than an adsorbed monolayer. Thus, it can be expected that procedures such as the mixing order during emulsion preparation are of crucial importance to the emulsification performance.  相似文献   

Cutaneous papillomavirus infection in a harbour porpoise (Phocoena phocoena) from the North Sea.     

M F Van Bressem  R A Kastelein  P Flamant  G Orth 《The Veterinary record》1999,144(21):592-593

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